The present invention concerns a motor vehicle seat with a seat cushion mounted on a seat frame, a backrest, and a fixing bracket for detachable fastening of an object placed on the seat cushion which is configured such that the fixing bracket can be swiveled from a covered out-of-use position into a functioning position in which the fixing bracket protrudes accessibly between the seat cushion and the backrest.
Such a motor vehicle seat is known from German document DE 196 50 087 C1. This document shows a device for detachable fastening of a child's seat in a motor vehicle seat with folding backrest. The device is rigidly connected with the bearing structure of the motor vehicle seat and arranged so that it is not disturbing in its resting position. The device has two mountings for a child's seat that are connected with the frame of the motor vehicle seat through a swivel axis. The mountings are brought out of their resting position into their functioning position when the backrest of the motor vehicle seat is folded forward and the mountings are swiveled into their functioning position. After swiveling the fixing bracket forward, the backrest is raised again. The disadvantage with this known device is the complicated serviceability of the mountings and the unavoidable folding of the backrest for swiveling the mountings from a resting position into a functioning position and back.
German document DE 101 60 236 C1 illustrates a child's seat which is suited for installation on a motor vehicle seat with such a mounting.
One object of this invention is the object of creating a motor vehicle seat with a mounting device which does not disturb objects placed on the motor vehicle seat when in the out-of-use position and which can be brought into the functioning position simply. Preferably, the holding device is constructed structurally simply, is comfortably operable, and offers a mechanically stable restraining point.
This object is accomplished by a motor vehicle seat having a swiveling device which has a four arm linkage that locks the fixing bracket in the functioning position, and with a fixing bracket which is U-shaped and connected fast with a shaft pivoted on the seat frame.
The motor vehicle seat of the invention has a swiveling device which swivels one or more, and preferably two, fixing brackets out of a concealed, out of use position into a functioning position. This swiveling device has a four bar linkage that locks the fixing bracket or brackets in a functioning position. This is advantageous in that the retaining device is not visible when not in use and is concealed and locked mechanically stably in the functioning position when in use. The four bar linkage or the fixing bracket is connected with a supporting element of the seat structure, preferably the seat frame, and can thus absorb large forces and pass them on to the support structure of the motor vehicle seat. Preferably, the four bar linkage is self-locking so that the four bar linkage automatically locks and mechanically secures the fixing bracket. This has an advantage in that, in the functioning position, the fixing bracket is, in any case, mounted firmly and mechanically stably.
When the fixing bracket is not in use, the swiveling device swivels the fixing bracket from the functioning position back into the out of use position. The four bar linkage can therefore be collapsed or folded together, and consequently requires as little structural space as possible.
In one construction, the four arm linkage has two levers connected rotatably with each other. These two levers form centers of rotation of the four arm linkage, since the two levers are connected rotatably with each other and since the first lever is rotatably connected with the fixing bracket and the second lever is rotatably connected with the supporting structure of the motor vehicle seat, preferably with a seat frame. The fixing bracket is connected so that it is capable of swiveling with the supporting structure of the motor vehicle seat whereby the shaft forms the fourth linkage of the four arm linkage.
The four arm linkage is especially arranged such that it occupies as little space as possible in the out of use position and forms a triangle of forces in the functioning position that accommodates the forces introduced into the fixing bracket from the object (for example, a child's seat) placed on the seat cushion, or passes them on to the supporting structure of the motor vehicle seat.
The two levers of the four arm linkage are arranged such that they are arranged at angles, preferably lying one on the other, in the out of use position. In this way, the levers lie close to each other, preferably beside each other, and occupy little space. In the functioning position of the fixing bracket, the two levers form a straight line and are consequently fitted to absorb tractive (tensile) and compressive forces along this line and to forward them to the supporting structure of the motor vehicle seat.
In one construction, the swiveling device has a Bowden cable that swivels the fixing bracket from the out of use position into the functioning position and holds it there. The four arm linkage locks the fixing bracket in the functioning position and therewith releases the Bowden cable. Forces introduced from an object such as a child's seat placed upon the seat cushion into the motor vehicle seat structure can become very high in the event of a crash. Since a Bowden cable can transmit high tractive forces but only small compressive forces, it is necessary for the Bowden cable to be mechanically released in the functioning position so as to be able to pass on the high forces arising during a crash securely into the motor vehicle structure and to be able to absorb the forces. The four arm linkage (which automatically locks in the functioning position) takes over this task and thereby passes on these forces into the seat structure.
The swiveling device has an energy storage unit, preferably a spring storage unit with mechanical or gas springs, that is charged when the fixing bracket is swung into the functioning position. The energy storage unit is constructed such that it automatically swings the fixing bracket back into the out-of-use position when discharged. Consequently, a secure and comfortable swinging back of the fixing bracket into the out-of-use position is guaranteed after locking of the fixing bracket is released. The energy storage unit can have a spring that acts upon the fixing bracket toward the out-of-use position.
One construction provides that the Bowden cable swings the fixing bracket from the out-of-use position into the functioning position against the restoring force of the energy storage unit. Advantageously the Bowden cable is arranged such that it is stressed under tension when the fixing bracket is swung into functioning position. The Bowden cable is capable of transmitting the tractive forces without difficulty, and moreover can charge the energy storage unit with the swinging motion.
In one construction, the Bowden cable is connected with the fixing bracket through the four arm linkage. In particular, the Bowden cable can be connected with the fixing bracket through the first lever, the second lever, or the four arm linkage. The Bowden cable can be manually or automatically actuated and, in particular, can be connected with an automatic motor for automatic activation of the fixing bracket.
In one construction, the Bowden cable is connected with a seat adjusting apparatus, for example a height adjusting apparatus and/or an inclination adjusting apparatus. In this way, the fixing bracket can be automatically swung in a preselectable seating position into the functional position, or only be swivelable into the functioning position in a preselectable seating position. This makes it possible for the motor vehicle seat to be in as secure as possible a seating position, preferably upright, for setting up a child's seat or a container.
The motor vehicle seat of the invention is especially suited for fastening children's seats with a so-called “isofix” fastening system, with two fixing brackets. The motor vehicle seat of the invention can be used in street motor vehicles, such as, for example, passenger cars or busses. Likewise use of the motor vehicle seat in rail motor vehicles in conceivable.